Bangkok. National carrier Thai Airways International PCL swung to a quarterly operating profit, but warned competition was likely to intensify after a UN body last month removed a ban on new international flights by Thai-based carriers.

Low-cost rivals Thai Vietjet, NokScoot and Thai AirAsia X have said they plan to add flights to destinations in Asia, increasing pressure on the legacy carrier, which like Singapore Airlines Ltd and Cathay Pacific Airways Ltd has reported falling ticket prices.

Thai Airways, 51 percent owned by the government, swung to an operating profit of 739 million baht ($22.33 million) for the third quarter ended Sept. 30, from a 836 million baht loss a year ago.

Revenue rose 6.3 percent to 46.9 billion baht as it boosted capacity and filled a higher percentage of seats, but reported a 7.5 percent decline in average fares.

The airline said competition was likely to intensify as new routes were opened and the industry faced shortages of trained pilots, flight attendants, engineers and technicians.

"The operating environment for full-service carriers in the Asia region remains highly challenging, especially on international routes, given intense price competition and strong capacity additions from both low-cost carriers and other full-service carriers," DBS analyst Paul Yong said, adding that higher fuel prices also would be a challenge.

Thai Airways' expenses rose 2.7 percent in the third quarter as jet fuel prices spiked and the government began taxing jet fuel for domestic routes.